Optically stimulated luminescence is a method of determining the age of burial of quartz or feldspar bearing sediments based upon principles of radiation and excitation within crystal lattices, and stems from the fact that imperfections in a crystal lattice have Osl dating wollongong ability to store ionizing energy Aitken; Botter -Jensen et al.
"Osl dating wollongong" Radiation within sediments comes from alpha, beta, and gamma radiation emitted during the decay of U, U, Th, 40 K, and 87 Rb, and their daughter products, both within Osl dating wollongong mineral grains and in their surroundings Lian, and from cosmic rays Figure 1.
Under controlled laboratory conditions, assuming the sample was collected under light-restricted conditions, controlled exposure of the sample to photons yields a luminescence response the equivalent dose, D ethe intensity of which is a function of the dose rate within the sediment, and the length of time the sample was exposed to the background radiation.
In order to measure the age, two factors must be known; 1 the environmental dose rate, and 2 the laboratory dose of radiation that produces the same intensity of luminescence as did the environmental radiation dose the equivalent dose.
Dividing the equivalent dose by the dose rate yields time. Samples for OSL analysis are typically collected from opaque core tubes aluminum or black pvc tubes that are pushed into the sediment using coring equipment vibracoregeoprobe"Osl dating wollongong." Samples are then extracted for processing under dark-room conditions. This is followed by sieving, heavy liquid Li- or Na- polytungstate separation, and sometimes magnetic separation to concentrate quartz sands of the appropriate size.
All of the processing must be done under dark-room conditions. The single aliquot regeneration SAR protocol Murray and Wintleis the technique of choice for a variety of applications, and was used for analyses
Osl dating wollongong with this USGS investigation. This is done by first exposing the sample aliquot to a known quantity of photons blue wavelength and determining the luminescence that occurs in response.
The sample is then irradiated with increasing radiation levels betaand re-exposed to determine the luminescence that occurs at each irradiation level.
The equivalent dose is then determined by applying a regression to the data, and determining the radiation dose that corresponds to the initial luminescence signal.
Determining the age is then a simple function of dividing the paleodose by the dose rate that is measured on the surrounding sediments. This is a much simplified explanation — there is more involved; e. "Osl dating wollongong" processes that produce the luminescence signal steps 1 and 2and the sampling and analytical procedure to determine the age of deposition steps 3 through 6.
An Introduction to Optical Dating. Investigations of the effects of pedoturbation on luminescence dating.
Preserving the paleoenvironmental record in drylands: Optically Stimulated Luminescence Dosimetry. Encyclopedia of Quaternary Science. And WintleA. Radiation Measurement s, 32, Wollongong, Australia.
Definition Uncertainties. As with any method, results of luminescence dating contain errors or uncertainties. Adequate. Postdoc, University of Wollongong (); PhD, the University of Hong Kong ( ) Developing luminescence dating techniques quartz and feldspar;.
Testing of young quartz and environmental sciences, wollongong. Jacobs, school of earth and feldspar grainsmore.